Between Oct. 1, 2016 and the end of April 2017, Portland, Oregon, experienced more than 145 days of rain, equaling 45.5 inches. Building code requirements vary across the United States, and in Oregon, rain screens have become a major topic of conversation due to the wet weather. After meeting structural requirements, water management in exteriors has established itself as a top priority, especially in wet climates.

New Rules. Extract from the updated code.

To help prevent issues like mold, rain screens are installed behind the cladding to direct water down and out quickly instead of keeping it in the walls. Rain screens are typically achieved by installing furring strips or some other means to achieve a drainage space between the exterior cladding and water-resistive barrier.

“In wet climates like those in Oregon, drainage is imperative to the long-term health and durability of a building,” said Kurt Koch, vice president of product innovation and engineering at Huber Engineered Woods LLC. “Managing moisture and airflow correctly in the exterior wall assembly is critical to helping structures last longer and stand up to inclement weather.”

An Exception and a Product Solution

There is an exception to the requirement for a rain screen. The additional step of creating a gap between the cladding and WRB can be eliminated if the WRB is manufactured in a manner that results in 75 percent or greater drainage efficiency, in accordance with ASTM 2273. ZIP System® sheathing and tape is an alternative to traditional sheathing and housewrap that helps Oregon builders comply with code requirements by streamlining materials and installation. The unique built-in water-resistive barrier integrated onto the ZIP System® sheathing surface achieves greater than 90 percent drainage efficiency, according to third-party report UEL-5010 publishing ZIP System sheathing compliance with ASTM E2273 requirements.

“Inspectors aren’t only looking at WRB installation (IRC R703.2), but also drainage efficiency, and that means more time and money are at stake,” added Brent Flotkoetter, general manager of ZIP System products. “By using high-quality products that meet or exceed code requirements using a minimal number of steps, builders will be able to stay ahead of the code and the competition.”

ZIP System sheathing and tape includes taped panel seams using advanced acrylic ZIP System™ tape. The system creates not only a Structural 1-rated wall assembly with an enhanced drainage plane, but also a continuous rigid air barrier all in two easy steps: hang the panels and tape the seams.